Cabo San Lucas, where it's located

The climate of Cabo San Lucas is tropical desert, with a pleasantly warm winter from December to March, and a hot summer from May to October, within which there is a relatively rainy period from July to September.
The city is located on the southern tip of the California Peninsula, in Los Cabos municipality. We are at the meeting point between the Gulf of California (or Sea of Cortez) and the Pacific Ocean, that is, between two different worlds.
In winter, when cool air arrives from the United States, some days can be a bit cool and windy, with the night temperature dropping to 8/10 °C (46/50 °F), but even in these cases, in the daytime it usually remains above 20 °C (68 °F). On the hottest days of the year, which can occur from May to October, the temperature generally reaches 38/39 °C (100/102 °F). In summer, the temperature is slightly lower than in the neighboring city of San José del Cabo. During the summer, the humidity gradually increases, and the muggiest month is September. However, even in summer the temperature can drop when the wind blows from the ocean.
From June to November, but with a higher probability from August to October, the Baja California peninsula can be affected by hurricanes of the Pacific Ocean, as happened with Hurricane Odile in September 2014. However, hurricanes are rare in June, the month in which they are most frequent is September, and historically they have never occurred in November.
The average temperature of the coldest month (January) is of 19.2 °C (67 °F), that of the warmest month (August) is of 29 °C (84 °F). Here are the average temperatures.
Cabo San Lucas - Average temperatures
Min (°C)131314151719232424211814
Max (°C)252627293132333433322927
Min (°F)555557596366737575706457
Max (°F)777981848890919391908481

Precipitation amounts to 220 millimeters (8.7 inches) per year: it is therefore scarce. It ranges from 0 mm (0 in) in the driest months (from March to June) to 80 mm (3.1 in) in the wettest (September). Here is the average precipitation.
Cabo San Lucas - Average precipitation

On average, there are around 2,860 sunshine hours per year. The sun shines all year round, but especially in the dry period. Here are the average sunshine hours per day.
Cabo San Lucas - Sunshine

The sea temperature ranges between 22 °C (72 °F) and 29 °C (84 °F). The sea is pleasantly warm from July to November, while from January to May, it is a bit cool but all in all acceptable for swimming. Here are the average sea temperatures.
Cabo San Lucas - Sea temperature
Temp (°C)232222222324272929282725
Temp (°F)737272727375818484828177

Cabo San Lucas

Best Time

Cabo San Lucas can be visited from mid-November to March, as it is the mildest season. During the day you can enjoy the sun, while in the evening you will need a sweater and a light jacket.
For a beach holiday, you may prefer May (when the sea is still a little cool, and a light jacket for the evening may also be needed) and the first half of November (when the sea is warmer).